Clockwork for mechanical time fuses



Nov.26,19 57 G. KUQN ETAL v 2,814,251

CLOCKWORK FOR MECHANICAL TIME FUSES Filed Jan. 12, 1955 s Sheets-Sheet 1 v INN TO RS Geores Kuhn Francis Liercgnze,

ATTORNEY Nov. 26, 1957 G. KUHN ET AL 2,814,251

CLOCKWORK FOR MECHANICAL TIME FUSES Filed Jan. 12, 1955 Sheets-Sheet 2 43 32 v if? 39 INVENTORS Georges uizm Francis Lien? me ATTORN Nov. 26, 1957 G. KUHN ETAL 2,814,251

CLOCKWORK FOR MECHANICAL TIME FUSES Filed Jan. 12, 1955 3 Sheets-Sheet 5 7 i Q Q l 7 INVENTURS Georges Kuhn, Mancis iengme.

ATTOR NEY 2,8 14,251 Patented Nov. 26, 1 957 CLQCKWORK FOR MECHANICAL TIME FUSES Georges Kuhn and Francis Liengme, Geneva, Switzerland, assignors to Mefina S. A., Fribourg, Switzerland,- a company of Switzerland Application January 12, 1955, Serial No. 481,432

Claims priority, application Switzerland September 4, 1954 4 Claims. (Cl. 102-84) Our invention has for its object a clockwork for mechanical time fuses incorporating means for holding and releasing the firing pin or striker, the striker in the fuse being submitted to the pressure of a spring and being held in its inoperative position by a bolt the location of which is controlled by a bell-shaped member or crown provided with a lateral opening through which said bolt may withdraw so as to release the striker, said bell-shaped member being rigid with a driving spindle submitted to the action of a spring which urges it into rotation.

The clockwork according to our invention is characterized by a member independent of the bell-shaped member and rigid with a movable part of the clockwork, which movable part is angularly shifted when setting the fuse, an abutment mem-ber locking the bell-shaped member during the inoperative period and during the setting of the fuse against the action of the spring on said bellshaped member with reference to the above-mentioned movable part of the clockwork in such a position that said independent member is held in a position in which it prevents the passage of the bolt through the lateral opening in the bell-shaped member; furthermore in the inoperative position a stop prevents the release of the abutment member which is only released after setting of the fuse, through the action of the axial acceleration to which the projectile provided with the fuse is submitted at the moment of the firing.

We have illustrated by way of example in accompanying diagrammatic drawings a preferred embodiment of our improved arrangement. In said drawings:

Fig. 1 is an axial sectional view of the arrangement.

Pig. 2 is a cross-section through line IIII of Fig. 1 showing the arrangement in its inoperative or stored condition i. e. in its striker locking position.

Fig. 3 is a cross-section similar to that of Fig. 2 showing the arrangement when inoperative after setting.

Fig. 4 is a cross-section similar to Figs. 2 and 3 showing the arrangement in its striker-releasing position.

The arrangement illustrated in accompanying drawings has for its object to ensure and to produce the release of the striker in a mechanical time fuse under the action of a clockwork. In such a fuse, the striker 1 is submitted to the pressure of a spring 2 and is held in its inoperative position by a bolt 3. The position of said bolt 3 is controlled by a bell-shaped member 4. The latter is provided with a lateral opening 5 through which the bolt 3 may Withdraw so as to release the striker 1. As readily apparent from inspection of Figs. 1 and 2, the bolt 3 is adapted to rock round the spindle 6 and carries a stud 7 adapted to engage the inner wall 8 of the bell-shaped member 4. Furthermore, as shown in Fig. 1, the part of the bolt ,3 engaging the collar 9 of the striker 1, is provided with a sloping surface 10 so that the striker 1 has a tendency to produce under the action of the spring 2, a receding movement of the bolt 3 i. e. a projection of the stud 7 through the opening 5 inthe bell-shaped member 4.

Said bell-shaped member 4 is rigid with a driving shaft 11 submitted to the action of a spiral spring 12 which urges it into rotation. As apparent from inspection of Fig. 1, said spring 12 is housed inside a cylindrical member 13 forming the motor frame. The outer end of the spiral spring 12 is rigidly secured to the motor frame 13 through a rivet 14 while its inner end is provided with an opening 15 which engages a projection 16 on the driving spindle 11. On said spindle, which forms thus a barrel arbor is fitted a large toothed annulus 17 adapted to drive the regulator lying in the upper section of the clockwork. Said regulator includes the gears 17- 19 and 20 driven by the pinion 21 meshing with said large toothed annulus 17. Said gears drive in their turn the balance 22 suspended to a spring 23 arranged along the axis of the clockwork. Said balance 22 controls the escape gear of the clockwork. The regulator system is contained inside the regulator housing 24. Said housing is closed at its upper end by a plate 25 carrying a balance-locking arrangement including two associated levers 26 pivotally secured each to a stud 27 and each carrying a depending projection 28 passing through an arcuate opening 29 in the plate 25. Each lever 26 is submitted to the action of a spring 30 which holds the projection 28 in contacting relationship with the balance 22 so as to lock the latter. Such an arrangement can be released only after the firing of a shot, under the action of the centrifugal force acting on the levers 26 so as to urge them apart and to release the balance 22. Such a locking device has been already described in the patent application Serial No. 222,344 filed April 23, 1951, which has matured into U. S. Patent No. 2,741,185.

As illustrated in Fig. 1, the motor frame 13 and the regulator housing 24 are rigid with one another as provided by a plate 31 and they form together the movable section of the clockwork. The motor frame 13 and also the regulator housing 24 are fitted inside a stationary housing 32 provided at its lower end with a cover 33 carrying a central inwardly projecting tubular part 34 forming a guiding pivot for the driving spindle 11 through its outer periphery and as a bush for the striker 1 through its axial bore. Said cover 33 carries the pivot 6 for the bolt 3 and it is provided furthermore with feet 35 adapted to connect it with the stationary section of the fuse and consequently with the projectile. The arrangement for holding and releasing the striker 1 of the fuse includes furthermore a member independent of the bell-shaped member 4. As shown in Fig. 1, said independent member 36 is secured through a screw 37 to the motor frame 13 i. e. to the movable section of the clockwork which section is rotated when setting the fuse.

On the other hand, a stop member, in the present case a catch 38 pivotally mounted on a pin 39 fitted in the motor frame 13 is adapted to lock the bell-shaped member 4 against the action of the spiral spring 12, with reference to the movable section 1324 of the clockwork. As illustrated in Figs. 1 and 2, the bell-shaped member 4 is provided to this end with a notch 40 inside which the catch 38 is engaged through its tip 41 so as to produce the locking of said member 4 with reference to the movable section 13-24 of the clockwork.

The location of the notch 40 and also the positions assumed by the member 36, the catch 38 and the opening 5 in the bell-shaped member are such that, when inoperative and also during the setting of the fuse, a nose 42 on the independent element 36 registers with the opening 5 in the bell-shaped member 4 and prevents thus the stud on the bolt 3 from passing through the opening 5 in the bell-shaped member 4. Furthermore, a stop 44 secured to thecover 33 prevents during the inoperative period, the release of the catch 38. As a mat ter of fact, the latter should be released only after setting of the fuse, under the action of the axial acceleration to which the projectile is submitted when a shot is fired. The clockwork also includes a small mass 45 housed inside a recess 46 formed inside the movable section 13-24 in close proximity with the location of the catch 38. Said small mass 45 is adapted to slide longitudinally inside its recess 46 under the action of the axial acceleration produced at the firing of the shot and it is adapted when sliding at such a moment to act on the catch 38 so as to make the latter rock, which constrains its tip 41 to move out of the notch 40 of the member 4. As illustrated in Fig. 1, said small mass 45 is rigid with a spring blade 47 adapted to prevent the return into its starting position of the small mass 45 when a shot has been fired, because said blade 47 is adapted to enter a groove 48 in the stationary frame 32 after the shot has been fired so as to lock the small mass 45 in the position assumed by it at the moment of the firing.

In such a clockwork, the spring 12 is tensioned to a sufiicient amount before the clockwork is mounted, so as to ensure its operation for the maximum setting to be considered. The setting of the fuse is obtained by rotating with reference to each other, on one hand, the movable section of the clockwork constituted by the parts 1324 and, on the other hand, the stationary frame section constituted by the member 32. Said two sections of the clockwork are held in their relative angular position by the mutual friction of the parts and in particular through the friction of the member 24 inside the upper part of the member 32. To allow an adjustment of the amount of operative friction, the upper part of said member 32 is provided with longitudinal slots and with a thread 49. A ring 50 is screwed onto said upper part of the member 32 over said thread 49. Said ring 50 is provided with an inner frustoc-onical surface 51 engaging a corresponding frustoconical surface 52 on the member 32. It will be readily ascertained that the screwing to a Variable extent of the ring 59 over the member 32 produces a corresponding clamping of the upper section of the member 32 over the regulator casing 24.

The operation of the above-described clockwork and in particular that of the arrangement adapted to hold and to release the fuse striker 1 is as follows:

As disclosed hereinaabove, the catch 38 prevents during the storing or inoperative period (Figs. 1 and 2), the rotation of the bell-shaped member 4 under the action of the spring 12, and it holds said member 4 in a manner such that the opening lies in a position for which the bolt 3 may be released, said bolt being however held in its striker-holding position by the independent member 36 the nose 42 of which engages the outer edge 43 of the bolt 3. In such a position, the striker 1 is locked g y tile sloping plane of the bolt 3, as shown in When it is desired to set the fuse, the movable section 13--24 of the clockwork is shifted angularly through a predetermined angl-e inside the stationary frame 32. Fig. 3 shows the location of the different parts of the locking and releasing means for a delay of say 10 seconds. As shown in said Fig. 3, the bolt 3 mounted on the cover 33 retains its original position when the bellshaped member 4 has been shifted together with the catch 38 and the element 36 by the above-mentioned predetermined angle so that the nose 42 of the element 36 still registers with the opening 5 in the member 4. In this position, the bolt 3 engages through its stud 7 the inner wall 8 of the bell-shaped member 4. However, as shown in said Fig. 3, the catch 38 is no more in contact with the stop 44 after setting of the fuse and nothing prevents its rocking except its high friction against the edge of the notch 40 in the bell-shaped member 4.

When the projectile has been fired, the small mass 45 is shifted downwardly with reference to its position shown in Fig. l by reason of its inertia, under the action of the considerable acceleration to which said projectile is submitted inside the gun barrel and, since the catch 38 is no longer locked by the stop 44, it rocks as a consequence of the impact of the small mass 45 against it and it releases the bell shaped member 4. From this moment onwards, the barrel spring 12 is allowed to drive the bellshaped member 4 and to make it rotate since the locking levers 26 have released the balance 22 engaged up to this moment by their projections 28. The opening 5 in the bell-shaped member moves then nearer and nearer the stud 7 on the bolt 3 and, as soon as it registers with the latter, the said stud 7 engages the opening 5 on one hand under the action of the centrifugal force acting on the bolt 3 and on the other hand under the action of the radial component of the thrust produced by the engagement of the collar 9 of the striker 1 on the sloping plane 14) of the bolt 3. The striker 1 is thus released and under the action of the spring 2, it ignites the primer of the projectile so as "to produce the explosion of the charge of the latter.

It should be remarked that in this arrangement the shape and the size of the nose 42 on the member 36 are such that said nose 42 prevents the bolt 3 from passing through the opening 5 in the bell-shaped member 4 not only when the fuse is inoperative but also when setting the fuse to an angle which is smaller than the angle corresponding to the minimum trajectory security of the projectile.

It is also possible to obtain this safeguard as to the minimum trajectory security of the fuse by sizing the stop 44 in a manner such that the latter does not allow any release of the catch 38 until the minimum setting angle has been reached. Thus, the stop 44 would not only provide safety during transportation against shocks and trepidations but also safety when the projectile starts moving on its path. It should be remembered that the levers 26 locking the balance 22 form also a safety means during transportation.

One of the major advantages of the above-described arrangement consists in the fact that the fuse may be set by shifting in either direction the movable section 13-24 with reference to the stationary section 32 of the clockwork. It is only the final angular position obtained after setting which defines the value of the latter, independently of the angle traversed by the movable section on its path before it reaches said final position.

We claim:

1. In a mechanical time fuse adapted to be fitted on a projectile having a primer, the combination comprising a stationary housing, a regulator housing, and a motor frame, said motor frame being fixed to said regulator housing, said motor frame and said regulator housing being positioned within said stationary housing, said motor frame and said regulator housing being rotatable with respect to said stationary housing and having a recess therein, said stationary housing having a cover therefor, said cover having an opening therethrough, an inwardly projecting hollow tubular member fixed to said cover in coinciding relationship with said opening, a driving shaft positioned about said tubular member, whereby said tubular member forms a guiding pivot for said driving shaft, a regulator means for timing the driv ing shaft, said means being operatively connected to said driving shaft, a firing pin positioned in said hollow tubular member, said firing pin having a collar portion adjacent its lower tip portion, a spring means for urging said firing pin in its operative position against said primer, said spring means being positioned in said hollow tubular member about said firing pin and resting on said collar portion, a bell-shaped member fixed to said driving shaft and coaxial therewith, said bell-shaped member having a lateral opening therethrough, a bolt means for holding said firing pin in its inoperative position against said spring means, said bolt means engaging said firing pin at the bottom surface of said collar, said bolt means being so positioned as to be able to withdraw through airliner said lateral opening of said bell-shaped member, a spindle positioned on said cover, said bolt means being rotatably mounted on said spindle, a stud member positioned on said bolt means and engaging the inner wall of said bellshaped member, a spiral spring means for urging said driving shaft and said bell-shaped member into rotation, said spiral spring means being fixed to said motor frame at its outer end and being operatively connected to said driving shaft at its inner end, said spiral spring being positioned within said motor frame, said motor frame being adapted to be angularly shifted around the axis of said bell-shaped member with respect to the position of the firing pin upon the setting of the fuse, a bolt stop means for preventing the passage of the bolt means through said lateral opening, said bolt stop means being fixed to said motor frame, said bolt stop means including a nose portion engaging said bolt means when said bolt means is in register with said lateral opening of said bell-shaped member, said nose portion extending peripherally of said bell-shaped member, a locking means for securing the bell-shaped member against the action of said spiral spring during the inoperative period, said locking means being pivotally mounted on said motor frame, whereby said bell-shaped member is held in such a position that said nose portion of said bolt stop means registers with said lateral opening in said bell-shaped member to prevent the passage of said stud on said bolt means therethrough, a stop means for holding said locking means in its operative position before the setting of the fuse, said stop member being fixed to said cover, and means for releasing said locking means upon the firing of the projectile, said means being positioned in the said recess of said motor frame and regulator housing, whereby the bell-shaped member may be released and caused to rotate under the action of said spiral spring means upon the firing of the projectile thereby releasing the firing pin against the projectile primer.

2. In a mechanical time fuse adapted to be fitted on a projectile having a primer, the combination comprising a stationary housing, a regulator housing, and a motor frame, said motor frame being fixed to said regulator housing, said motor frame and said regulator housing being positioned within said stationary housing, said motor frame and said regulator housing being rotatable with respect to said stationary housing and having a recess therein, said stationary housing having a cover therefor, said cover having an opening therethrough, an inwardly projecting hollow tubular member fixed to said cover in coinciding relationship with said opening, a driving shaft positioned about said tubular member, whereby said tubular member forms a guiding pivot for said driving shaft, a regulator means for timing the driving shaft, said means being operatively connected to said driving shaft, a firing pin positioned in said hollow tubular member, said firing pin having a collar portion adjacent its lower tip portion, a spring means for urging said firing pin in its operative position against said primer, said spring means being positioned in said hollow tubular member about said firing pin and resting on said collar portion, a bell-shaped member fixed to said driving shaft and coaxial therewith, said bell-shaped member having a lateral opening therethrough and also including a radial notch, a bolt means for holding said firing pin in its inoperative position against said spring means, said bolt means engaging said firing pin at the bottom surface of said collar, said bolt means being so positioned as to be able to withdraw through said lateral opening of said bell-shaped member, a spindle positioned on said cover, said bolt means being rotatably mounted on said spindle, a stud member positioned on said bolt means and engaging the inner wall of said bell-shaped member, a spiral spring means for urging said driving shaft and said bell-shaped member into rotation, said spiral spring means being fixed to said motor frame at its outer end and being operatively connected to said driving shaft at its inner end, said spiral spring being positioned within said motor frame, said motor frame being adapted to be angularly shifted around the axis of said bell-shaped member with respect to the position of the firing pin upon the setting of the fuse, a bolt stop means for preventing the passage of the bolt means through said lateral opening, said bolt stop means being fixed to said motor frame, said bolt stop means including a nose portion engaging said bolt means when said bolt means is in register with said lateral opening of said bell-shaped member, said nose portion extending peripherally of said bell-shaped member, a locking means for securing the bell-shaped member against the action of said spiral spring during the inoperative period, said locking means including a catch member, said catch member being pivotally mounted on said motor frame, said catch member including a tip portion frictionally engaging said bell-shaped member at said radial notch before and during the setting of the fuse, whereby said bell-shaped member is held in such a position that said nose portion of said bolt stop means registers with said lateral opening in said bellshaped member to prevent the passage of said stud on said bolt means therethrough, a stop means for holding said locking means in its operative position before the setting of the fuse, said stop member being fixed to said cover, and means for releasing said locking means upon the firing of the projectile, said means being positioned in said recess of said motor frame and regulator housing, whereby the bell-shaped member may be released and caused to rotate under the action of said spiral spring means upon the firing of the projectile thereby releasing the firing pin against the projectile primer.

3. In a mechanical time fuse adapted to be fitted on a projectile having a primer, the combination comprising a stationary housing, a regulator housing, and a motor frame, said motor frame being fixed to said regulator housing, said motor frame and said regulator housing being positioned within said stationary housing, said motor frame and said regulator housing being rotatable with respect to said stationary housing and having a recess therein, said stationary housing having a cover therefor, said cover having an opening therethrough, an inwardly projecting hollow tubular member fixed to said cover in coinciding relationship with said opening, a driving shaft positioned about said tubular member, whereby said tubular member forms a guiding pivot for said driving shaft, a regulator means for timing the driving shaft, said means being operatively connected to said driving shaft, a firing pin positioned in said hollow tubular member, said firing pin having a collar portion adjacent its lower tip portion, a spring means for urging said firing pin in its operative position against said primer, said spring means being positioned in said hollow tubular member about said firing pin and resting on said collar portion, a bell-shaped member fixed to said drawing shaft and coaxial therewith, said bell-shaped member having a lateral opening therethrough and also including a radial notch, a bolt means for holding said firing pin in its inoperative position against said spring means, said bolt means engaging said firing pin at the bottom surface of said collar, said bolt means being so positioned as to be able to withdraw through said lateral opening of said bell-shaped member, a spindle positioned on said cover, said bolt means being rotatably mounted on said spindle, a stud member positioned on said bolt means and engaging the inner wall of said bell-shaped member, a spiral spring means for urging said driving shaft and said bellshaped member into rotation, said spiral spring means being fixed to said motor frame at its outer end and being operatively connected to said driving shaft at its inner end, said spiral spring being positioned within said motor frame, said motor frame being adapted to be angularly shifted around the axis of said bell-shaped member with respect to the position of the firing pin upon the setting of the fuse, a bolt stop means for preventing the passage of the bolt means through said lateral opening, said bolt stop means being fixed to said motor frame, said bolt stop means including a nose portion engaging said bolt means when said bolt means is in register with said lateral opening of said bell-shaped member, said nose portion extending peripherally of said bell-shaped member, a locking means for securing the bell-shaped member against the action of said spiral spring during the inoperative period, said locking means including a catch member, said catch member being pivotally mounted on said motor frame, said catch member including a tip portion frictionally engaging said bell-shaped member at said radial notch before and during the setting of the fuse, whereby said bell-shaped member is held in such a position that said nose portion of said bolt stop means registers with said lateral opening in said bell'shaped member to prevent the passage of said stud on said bolt means therethrough, a stop means for holding said locking means in its operative position before the setting of the fuse, said stop member being fixed to said cover, and means for releasing said locking means upon the firing of the projectile, said releasing means including a small inertia mass longitudinally shiftable of said regulator housing under the action of the axial acceleration at the moment of the firing of the projectile, said inertia mass being positioned in said recess of said motor frame and regulator housing, whereby the catch of said locking member may be released from said radial notch at the moment of the said firing of the projectile thereby allowing said bell-shaped member to start rotating under the action of said spiral spring means thereby to release the firing pin against the projectile primer.

4. In a mechanical time fuse adapted to be fitted on a projectile having a primer, the combination comprising a stationary housing, a regulator housing, and a motor frame, said motor frame being fixed to said regulator housing, said motor frame and said regulator housing being positioned within said stationary housing, said motor frame and said regulator housing being rotatable with respect to said stationary housing and having a recess therein, said stationary housing having a cover therefor, said cover having an opening therethrough, an inwardly projecting hollow tubular member fixed to said cover in coinciding relationship with said opening, a driving shaft positioned about said tubular member, whereby said tubular member forms a guiding pivot for said driving shaft, a regulator means for timing the driving shaft, said means being operatively connected to said driving shaft, a firing pin positioned in said hollow tubular member, said firing pin having a collar portion adjacent its lower top portion, a spring means for urging said firing pin in its operative position against said P imer, said spring means being positioned in said hollow tubular member about said firing pin and resting on said collar portion, a bell-shaped member fixed to said driving shaft means engaging said firing pin at the bottomsurface of said collar, said bolt means being so positioned as to be able to withdraw through said lateral opening of said bell-shaped member, a spindle positioned on said cover, said bolt means being rotatably mounted on said spindle, a stud member positioned on said bolt means and engaging the inner wall of said bell-shaped member, a spiral spring means for urging said driving shaft and said bell-shaped member into rotation, said spiral spring means being fixed to said motor frame at its outer end and being operatively connected to said driving shaft at its inner end, said spiral spring being positioned within said motor frame, said motor frame being adapted to be angularly shifted around the axis of said bell-shaped member with respect to the position of the firing pin upon the setting of the fuse, a bolt stop means for preventing the passage of the bolt means through said lateral opening, said bolt stop means being fixed to said motor frame, said bolt stop means including a nose portion engaging said bolt means when said bolt means is in register with said lateral opening of said bell-shaped member, said nose portion extending peripherally of said bell-shaped member, a locking means for securing the bell-shaped member against the action of said spiral spring during the inoperative period, said locking means including a catch member, said catch member being pivotally mounted on said motor frame, said catch member including a tip portion frictionally engaging ssaid bell-shaped member at said radial notch before and during the setting of the fuse, whereby said bell-shaped member is held in such a position that said. nose portion of said bo-lt stop means registers with said lateral opening in said bellshaped member to prevent the passage of said stud on said bolt means therethrough, a stop means for holding said locking means in its operative position before the setting of the fuse, said stop member being fixed to said cover, and means for releasing said locking means upon the firing of the projectile, said releasing means including both a small inertia mass longitudinally shiftable of said regulator housing under the action of the axial acceleration at the moment of the firing of the projectile and a blade spring fixed to said inertia mass, said inertia mass being positioned in said recess of said motor frame and regulator housing, said stationary housing including a notch means in said recess for engaging said spring blade during the shifting of said small inertia mass and said blade spring fixed thereto upon the firing of the projectile and for holding said small inertia mass in its catch-releasing portion, whereby the catch of said locking member may be released from said radial notch at the moment of the said firing of the projectile thereby allowing said bell-shaped member to start rotating under the action of said spiral spring means thereby to release the firing pin against the projectile primer.

References Cited in the file of this patent UNITED STATES PATENTS 2,446,745 Delay Aug. 10, 1948 

